NASA Rocket Redefines What Astronomers Think of as Galaxies   
       
   Nov 6, 2014: A NASA sounding rocket experiment has detected a surprising   
   surplus of infrared light in the dark space between galaxies, a diffuse cosmic   
   glow as bright as all known galaxies combined. The glow is thought to be from   
   orphaned stars flung out of galaxies.   
       
   The findings redefine what scientists think of as galaxies. Galaxies may not   
   have a set boundary of stars, but instead stretch out to great distances,   
   forming a vast, interconnected sea of stars.   
       
   http://www.jpl.nasa.gov/spaceimages/details.php?id=pia18853   
       
   This is a time-lapse photograph of the Cosmic Infrared Background Experiment   
   (CIBER) rocket launch, taken from NASA's Wallops Flight Facility in Virginia   
   in 2013. The image is from the last of four launches. Image Credit: T.   
   Arai/University of Tokyo   
       
   Observations from the Cosmic Infrared Background Experiment, or CIBER, are   
   helping settle a debate on whether this background infrared light in the   
   universe, previously detected by NASA's Spitzer Space Telescope, comes from   
   these streams of stripped stars too distant to be seen individually, or   
   alternatively from the first galaxies to form in the universe.   
       
   "We think stars are being scattered out into space during galaxy collisions,"   
   said Michael Zemcov, lead author of a new paper describing the results from   
   the rocket project and an astronomer at the California Institute of Technology   
   (Caltech) and NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California.   
   "While we have previously observed cases where stars are flung from galaxies   
   in a tidal stream, our new measurement implies this process is widespread."   
       
   Using suborbital sounding rockets, which are smaller than those that carry   
   satellites to space and are ideal for short experiments, CIBER captured   
   wide-field pictures of the cosmic infrared background at two infrared   
   wavelengths shorter than those seen by Spitzer. Because our atmosphere itself   
   glows brightly at these particular wavelengths of light, the measurements can   
   only be done from space.   
       
   "It is wonderfully exciting for such a small NASA rocket to make such a huge   
   discovery," said Mike Garcia, program scientist from NASA Headquarters.   
   "Sounding rockets are an important element in our balanced toolbox of missions   
   from small to large."   
       
   http://www.jpl.nasa.gov/spaceimages/details.php?id=pia18855   
       
   CIBER measurements favor a model in which the IR glow between distant galaxies   
   is caused by orphan stars. MoreDuring the CIBER flights, the cameras launch   
   into space, then snap pictures for about seven minutes before transmitting the   
   data back to Earth. Scientists masked out bright stars and galaxies from the   
   pictures and carefully ruled out any light coming from more local sources,   
   such as our own Milky Way galaxy. What's left is a map showing fluctuations in   
   the remaining infrared background light, with splotches that are much bigger   
   than individual galaxies. The brightness of these fluctuations allows   
   scientists to measure the total amount of background light.   
       
   To the surprise of the CIBER team, the maps revealed a dramatic excess of   
   light beyond what comes from the galaxies.  The data showed that this infrared   
   background light has a blue spectrum, which means it increases in brightness   
   at shorter wavelengths. This is evidence the light comes from a previously   
   undetected population of stars between galaxies. Light from the first galaxies   
   would give a spectrum of colors that is redder than what was seen.   
       
   "The light looks too bright and too blue to be coming from the first   
   generation of galaxies," said James Bock, principal investigator of the CIBER   
   project from Caltech and JPL. "The simplest explanation, which best explains   
   the measurements, is that many stars have been ripped from their galactic   
   birthplace, and that the stripped stars emit on average about as much light as   
   the galaxies themselves."   
       
   Future experiments can test whether stray stars are indeed the source of the   
   infrared cosmic glow. If the stars were tossed out from their parent galaxies,   
   they should still be located in the same vicinity. The CIBER team is working   
   on better measurements using more infrared colors to learn how stripping of   
   stars happened over cosmic history.   
       
   Results from two of four CIBER flights, both of which launched from White   
   Sands Missile Range in New Mexico in 2010 and 2012, appear Friday, Nov. 7 in   
   the journal Science.   
       
   Credits:   
   Production editor: Dr. Tony Phillips | Credit: Science@NASA   
       
   More information:   
       
   For more information on NASA's sounding rocket experiments, visit:   
   http://www.nasa.gov/mission_pages/sounding-rockets/   
       
   For more information about CIBER, visit: http://ciber.caltech.edu/rocket.html   
       
   Caltech manages JPL for NASA. The work was supported by NASA, with initial   
   support provided by JPL's Director's Research and Development Fund. Japanese   
   participation in CIBER was supported by the Japan Society for the Promotion of   
   Science and the Ministry of Education, Culture, Sports, Science and   
   Technology. Korean participation in CIBER was supported by the Korean   
   Astronomy and Space Science Institute."   
       
       
   Regards,   
       
   Roger   
      
   --- D'Bridge 3.99   
    * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)